A former Norfolk MP was one of four board members who quit the government’s Social Mobility Commission in protest at the lack of progress towards a “fairer Britain”.

Former South West Norfolk member of parliament Baroness Gillian Shephard quit along with Alan Milburn, the former Labour minister who heads the commission.

Mr Milburn said he had “little hope” the current government was capable of making the changes necessary to deliver a more equal society.

The other two commissioners to step down were David Johnston, the chief executive of the Social Mobility Foundation charity, and Paul Gregg, a professor of economic and social policy at the University of Bath.

The resignations are a major setback for Prime Minister Theresa May who promised to tackle the “burning injustices” that hold back poorer people.

However, a government spokesman said the departures came after Mr Milburn - whose term as commission chair expired last July - was told that a new chair was to be appointed and that an open application process would be held for the role.

In his resignation letter, Mr Milburn said the preoccupation with Brexit meant the government “does not have the necessary bandwidth to ensure the rhetoric of healing social division is matched with the reality”.

He added: “I have little hope of the current government making the progress I believe is necessary to bring about a fairer Britain.

“It seems unable to commit to the future of the commission as an independent body or to give due priority to the social mobility challenge facing our nation.”

The resignations come just days after the commission warned that unless the economic, social and local divisions laid bare by the Brexit vote were addressed there would be a rise in far right or hard left extremism.

For Labour, shadow cabinet office minister Jon Trickett said the resignations came as “no surprise”.

“As inequality has grown under the Tories, social mobility has totally stalled. Theresa May has rewarded the rich whilst holding everyone else back,” he said.

“It is no surprise the whole Social Mobility Commission has resigned in frustration. Under the Tories, how well people do in life is still based on class background rather than on talent or effort.”